A vet who used to work at the Flemington Equine Clinic has been found guilty of six cobalt charges.

Racing NSW issued the charges against Dr Adam Matthews on Thursday following a two-day hearing in October along with further written submissions from steward Ray Murrihy and the vet's legal counsel.

Matthews was found guilty of being a party to the race-day treatment of the Sam Kavanagh-trained Midsummer Sun prior to the horse's Gosford Cup win in January.

Stewards ruled he supplied two bottles of `Vitamin Complex' to Flemington Equine Clinic colleague Dr Tom Brennan, who is alleged to have given them to Kavanagh for use on his racehorses.

Telephone records from Matthews, Kavanagh and harness racing identities John Camilleri and Mitchell Butterfield were used as evidence to support the stewards' case.

They showed a series of text messages and conversations between Matthews and Kavanagh on the day before, and day of, Midsummer Sun's Gosford Gold Cup win.

While Matthews and Kavanagh gave conflicting evidence on the topics they discussed, stewards accepted Kavanagh's testimony in which he admitted they talked about the race-day treatment of the horse.

Stewards said the timing and content of the telephone communications between the two supported Kavanagh's submissions.

In finding Matthews guilty of supplying the bottles of "Vitamin Complex", stewards referred to a text message exchange between the vet and Kavanagh on January 13 after news broke that a horse trained by Peter Moody had returned a cobalt irregularity.

Kavanagh sent a message to Matthews asking: "Are us (sic) sure we are ok" and when Matthews responded with a series of question marks, Kavanagh sent another text "Drips moody gone cobalt".

Kavanagh was earlier this year disqualified for nine years and three months over his role in the Midsummer Sun saga.

Brennan was banned for six years while Camilleri and Butterfield were disqualified for 4-1/2 years and 21 months respectively.